1998 ISUZU TROOPER relay

8DÐ134 WIRING SYSTEM
Diagnosis
Quick Chart for Check Points
1. Headlight (RHD)
Check point
Trouble modeFuse
F–4
(15A)F–5
(15A)Lighting
relayLighting
SWDimmer•
Passing
SWCable
harness Headlight
bulb
1–1. Both Headlights inoperative
1–2. Headlight on the left (or
right) side inoperative
1–3. Both headlights in
low-beam inoperative
1–4. Headlight low-beam on
the left (or right) side
inoperative
1–5. Both headlights in
high–beam inoperative
1–6. Headlight high-beam on the
left (or right) side
inoperative
1–7. Headlight beam does not
change
LH RH
1–8. Headlights remain on when
the lighting SW is turned off
1–9. Headlights come on with
the lighting SW at the
clearance light position
1–10. Passing lights inoperative

WIRING SYSTEM 8DÐ135
Check point
Trouble modeFuse
F–4
(10A)F–5
(10A)Dimmer
relayLighting
SWDimmer•
Passing
SWCable
harness Headlight
bulb
2–1. Both Headlights
inoperative
2–2. Headlight on the
left (or right) side
inoperative
2–3. Both headlights
in low-beam
inoperative
2–4. Headlight low-
beam on the left
(or right)
side inoperative
2–5. Both headlights
in high-beam
inoperative
2–6. Headlight
high-beam on
the left (or right)
side inoperative
2–7. Headlight beam
does not change
Lighting
relayF–6
(10A)F–7
(10A)
2–8. Headlights
remain
on when the
lighting SW is
turned off
2–9. Headlights come
on with the
lighting SW at
the clearance
light position
Diode
2–10. Passing lights
inoperative
LH
RH
2. Headlight (LHD)

8DÐ136 WIRING SYSTEM
Check point
Trouble modeFuse
F–8
(15A or 20A)Cable
harness Fog light
bulb
3–1. Both FRT fog lights
inoperative
(while the clearance light is ON)
3–2. FRT fog light on the left
(or rigth) side inoperative
(while the clearance light is ON)
LHRH
FRT
fog light
SWFRT
fog light
relayRR
fog light
SWRR
fog light
relay
3. FRT fog lights

WIRING SYSTEM 8DÐ137
1-1. Both Headlights Inoperative
·IS THE LIGHTING RELAY NORMAL?
YES
·IS B-19 GROUNDED SECURELY?
YES
REPLACE THE LIGTHING RELAY
NO
·DISCONNECT THE LIGTHING SW CONNECTOR
·IS THE BATTERY VOLTAGE APPLIED BETWEEN THE HARNESS
SIDE CONNECTOR 1 B-12 AND GROUND?
YES
GROUND IT SECURELY
NO
·REMOVE THE LIGHTING SW
·IS THERE CONTINUITY BETWEEN 1 B-12 AND 7 B-12 WHEN
SETTING THE LIGHTING SW AT THE HEADLIGHT POSITION ?REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN THE FUSUBLE LINK
FL-1 (80A) AND 1 B-12
NO
YES
REPAIR OR REPLACE THE LIGHTING SW
NO
REPAIR A POOR CONNECTION AT THE CONNECTORS OR AN
OPEN CIRCUIT BETWEEN THE HARNESS SIDE CONNECTOR
7 B-12 AND B-19
·IS THE DIODE NORMAL?
REPLACE THE DIODE
NOYES

WIRING SYSTEM 8DÐ141
1-7. Headlight Beam Does Not Change
1-8. Headlights Remain On When The Lighting SW Is Turned Off
YES
·DISCONNECT THE DIMMER•PASSING
SWREPAIR OR REPLACE THE DIMMER•PASSING SW
NO
·DOES THE LEVER OF THE DIMMER•
PASSING SW OPERATE SMOOTHLY AND SECURELY?
·WITH THE SWITCH AT THE LOW-BEAM POSITION, IS
THERE CONTINUITY BETWEEN 13 B-12 AND 16 B-12 ?
ALSO, WITH IT AT THE HIGH-BEAM POSITION, IS THERE
CONTINUITY BETWEEN 15 B-12 AND 16 B-12 ?
NO
REPAIR OR REPLACE THE DIMMER•PASSING SW
YES
·REPLACE THE LIGHTING RELAY
NO
·IS THE LIGHTING RELAY NORMAL?
REPAIR OR REPLACE THE LIGHTING SW
NO
DISCONNECT THE LIGHTING SW CONNECTOR
·IS THE CONTINUITY BETWEEN
THE SWITCH CONNECTOR TERMINALS 1 B-12 AND
7 B-12 NORMAL?
YES
REPAIR A SHORT CIRCUIT BETWEEN
5 X-1 AND 1 B-12

WIRING SYSTEM 8DÐ143
2-1. Both Headlights Inoperative
·IS THE LIGHTING RELAY NORMAL?
YES
REPLACE THE RELAY
NO
·IS B-19 GROUNDED SECURELY?
YESNO
GROUND IT SECURELY·IS THE DIODE NORMAL ?
YESNO
REPLACE THE DIODE
·IS THE DIMMER RELAY NORMAL?
YESNO
REPLACE THE RELAY·
·DISCONNECT THE LIGHTING SW CONNECTOR
YESNO
·
·REMOVE THE LIGHTING SW
YESNO
REPAIR A POOR CONNECTION AT THE CONNECTORS
OR AN OPEN CIRCUIT BETWEEN THE FUSIBLE LINK
FL-1 (80A) AND 1 B-12
REPAIR OR REPLACE THE LIGHTING SW REPAIR A POOR CONNECTION AT THE CONNECTORS OR
AN OPEN CIRCUIT BETWEEN THE LIGHTING SW HARNESS SIDE
CONNECTOR 7 B-12 AND B-19
IS THE BATTERY VOLTAGE APPLIED BETWEEN THE
HARNESS SIDE CONNECTOR 1 B-12 AND GROUND?
IS THERE CONTINUITY BETWEEN 1 B-12 AND 7 B-12 WHEN
SETTING THE LIGHTING SW AT THE HEADLIGHT POSITION?

8DÐ144 WIRING SYSTEM
2-2. Headlight On The Left (Or Right) Side Inoperative
·IS THE HEADLIGHT BULB ON THE LEFT (OR RIGHT) SIDE
NORMAL?
YES
REPLACE THE BULB
NO
·IS 7 C-39 (OR 5 C-39 ) GROUNDED SECURELY? (RH)
IS 4 C-39 (OR 7 C-16 ) GROUNDED SECURELY? (LH)
YESNO
GROUND IT SECURELY
REPAIR AN OPEN CIRCUIT BETWEEN
3 C-32 AND 7 C-39 (OR 5 C-39 ) (RH)
3 C-21 AND 4 C-39 (OR 7 C-16 ) (LH)
·IS THE DIMMER RELAY NORMAL?
YES
REPAIR A POOR CONNECTION AT THE CONNECTORS OR
AN OPEN CIRCUIT BETWEEN 2 X-3 AND FUSE F-6 (10A)
NO
REPLACE THE RELAY
2-3. Both Headlights In Low-Beam Inoperative

WIRING SYSTEM 8DÐ145
2-4. Headlight Low-Beam On The Left (Or Right) Side Inoperative
2-5. Both Headlights In High-Beam Inoperative
·IS THE HEADLIGHT BULB NORMAL?
YESNO
REPLACE THE BULB·IS THE FUSE F-6 (10A) (OR F-7 (10A)) NORMAL?
YES
REPAIR A POOR CONNECTION AT THE CONNECTORS OR
AN OPEN CIRCUIT BETWEEN FUSE F-6 (10A) AND 1 C-21
(OR FUSE F-7 (10A) AND 1 C-32 )
NO
REPLACE THE FUSE
·IS THE DIMMER RELAY NORMAL?
YESNO
REPLACE THE RELAY·
·DISCONNECT THE DIMMER·PASING SW CONNECTOR
IS THERE ANY CONTINUITY BETWEEN THE SWITCH SIDE
CONNECTOR 15 B-12 AND 16 B-12 WHEN THE
SWITCH IS AT HIGH-BEAM POSITION?
YESNO
REPAIR OR REPLACE THE SWITCH·IS THE BATTERY VOLTAGE APPLIED BETWEEN THE
HARNESS SIDE CONNECTOR 15 B-12 AND GROUND
WHEN THE SWITCH IS AT HIGH-BEAM POSITION?
YESNO
REPAIR A POOR CONNECTION AT THE CONNEC-
TORS OR AN OPEN CIRCUIT BETWEEN 5 X-3
AND 15 B-12REPAIR A POOR CONNECTION AT THE CONNECTOR OR AN
OPEN CIRCUIT BETWEEN 3 X-3 AND FUSE F-4 (10A)